1. Field of the Invention
The present invention relates to the detection of human intruders. More particularly, the invention as described and claimed herein relates to a dual-modality sensor constructed to accurately discern when movement detected within a secure setting, perimeter or border is human movement with a high probability of accuracy.
2. Description of the Related Art
In perimeter, border and building security applications, it is desirable to detect human intruders with a high probability of correct detection, and a low probability of false detection. False alarms are troubling in any security application, but much more so in critical security applications. Critical security applications require a response and/or investigation by security guards or personnel to any detected intrusion understood to be human. Where the detection is false, private security or local police must investigate nevertheless to verify the falsity. False alarm reports must be prepared and communicated. The entire false alarm operation, from investigation to reporting can be quite costly in terms of personnel response time, report preparation, and communication to local government and premise owners or managers. More importantly at times, false alarms generated by mistakenly detecting and falsely communicating a human intrusion may reduce a client's trust in a security system, or security system personnel associated with the false alarm raised.
Conventional human intruder sensing devices and systems may use various known sensor technologies to detect when a secure boundary has been breached. The sensor technologies include passive infrared (PIR) detectors, microwave detectors, seismic detectors, ultrasonic and other human motion detectors and systems. Such sensors detect human motion but also are susceptible to misidentifying non-human motion and falsely attributing the source of the non-human motion as human. False alarms are frequently raised when an animal breaches a secure border and is falsely detected and reported as a human intruder. For that matter, statistics show that most intruder detections generated by conventional motion-based perimeter and border security systems are the result of animal movement/intrusion rather than human. It follows that most alarms indicating a human intruder are false alarms (false positives).
Accordingly, there is a need for a new type of sensor, and security system using the sensor, which is capable of detecting or distinguishing human characteristics rather than mere motion to accurately qualify detections. By detecting human characteristics at a source of the motion, such a new and novel type sensor could better discern whether the source is human or non-human with many less false alarms. Preferably, such a new sensor and system would be inexpensive, battery-operated, and require no human assistance to distinguish between human and non-human intrusions.